Google sign in not working android webview app

Question

I\'ve created Android App with webview. When trying to sign in with Google, it first asks for username & password, then the screen with the message \'Please close this w

Answer 1

Two things in webview create problems in google sign-in.

1. Google doesn't allow us to sign-in from webview nowadays. So, User-Agent needs to be customized.
   
2. Popup handling in webview isn't appropriate. So, a function override is needed.
   

Using custom User-Agent and an AlertDialog in WebChromeClient to handle popups solve the issues for me.

Here's the full code:

public class MainActivity extends AppCompatActivity {

    private Context contextPop;
    private WebView webViewPop;
    private AlertDialog builder;

    private String url = "https://example.com";

    private WebView webView;
    private String userAgent;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        webView = findViewById(R.id.webView);
        webView.setWebViewClient(new WebViewClient());
        webView.loadUrl(url);

        WebSettings webSettings = webView.getSettings();
        webSettings.setJavaScriptEnabled(true);

        // Set User Agent
        userAgent = System.getProperty("http.agent");
        webSettings.setUserAgentString(userAgent + "WebViewApp Captain Earth/1");

        // Enable Cookies
        CookieManager.getInstance().setAcceptCookie(true);
        if(android.os.Build.VERSION.SDK_INT >= 21)
            CookieManager.getInstance().setAcceptThirdPartyCookies(webView, true);

        // WebView Tweaks
        webSettings.setRenderPriority(WebSettings.RenderPriority.HIGH);
        webSettings.setCacheMode(WebSettings.LOAD_DEFAULT);
        webSettings.setAppCacheEnabled(true);
        webSettings.setDomStorageEnabled(true);
        webSettings.setLayoutAlgorithm(WebSettings.LayoutAlgorithm.NARROW_COLUMNS);
        webSettings.setUseWideViewPort(true);
        webSettings.setSaveFormData(true);
        webSettings.setEnableSmoothTransition(true);
        webView.setScrollBarStyle(View.SCROLLBARS_INSIDE_OVERLAY);

        // Handle Popups
        webView.setWebChromeClient(new CustomChromeClient());
        webSettings.setJavaScriptCanOpenWindowsAutomatically(true);
        webSettings.setSupportMultipleWindows(true);
        contextPop = this.getApplicationContext();
    }

    @Override
    public void onBackPressed() {

        if(webView.canGoBack()) {
            webView.goBack();
        }
        else {
            super.onBackPressed();
            // Terminate the app
            // finishAffinity();
            // System.exit(0);
        }
    }

    class CustomChromeClient extends WebChromeClient {

        @Override
        public boolean onCreateWindow(WebView view, boolean isDialog,
                                      boolean isUserGesture, Message resultMsg) {
            webViewPop = new WebView(contextPop);
            webViewPop.setVerticalScrollBarEnabled(false);
            webViewPop.setHorizontalScrollBarEnabled(false);
            webViewPop.setWebChromeClient(new CustomChromeClient());
            webViewPop.getSettings().setJavaScriptEnabled(true);
            webViewPop.getSettings().setSaveFormData(true);
            webViewPop.getSettings().setEnableSmoothTransition(true);
            webViewPop.getSettings().setUserAgentString(userAgent + "WebViewApp Captain Earth/1");

            // set the WebView as the AlertDialog.Builder’s view
            builder = new AlertDialog.Builder(MainActivity.this, AlertDialog.THEME_DEVICE_DEFAULT_LIGHT).create();
            builder.setTitle("");
            builder.setView(webViewPop);

            builder.setButton("Close", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int id) {
                    webViewPop.destroy();
                    dialog.dismiss();
                }
            });

            builder.show();
            builder.getWindow().clearFlags(WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE|WindowManager.LayoutParams.FLAG_ALT_FOCUSABLE_IM);

            CookieManager cookieManager = CookieManager.getInstance();
            cookieManager.setAcceptCookie(true);
            if(android.os.Build.VERSION.SDK_INT >= 21) {
                cookieManager.setAcceptThirdPartyCookies(webViewPop, true);
                cookieManager.setAcceptThirdPartyCookies(webView, true);
            }

            WebView.WebViewTransport transport = (WebView.WebViewTransport) resultMsg.obj;
            transport.setWebView(webViewPop);
            resultMsg.sendToTarget();

            return true;
        }

        @Override
        public void onCloseWindow(WebView window) {
            //Toast.makeText(contextPop,"onCloseWindow called",Toast.LENGTH_SHORT).show();
            try {
                webViewPop.destroy();
            } catch (Exception e) {
                Log.d("Webview Destroy Error: ", e.getStackTrace().toString());
            }

            try {
                builder.dismiss();
            } catch (Exception e) {
                Log.d("Builder Dismiss Error: ", e.getStackTrace().toString());
            }

        }
    }
}